A caterpillar or caterpillar tree is a tree in which all the vertices are within distance 1 of a central path.
How to define caterpillar graphs in sage? is it already implemented?
Kindly help me with this.
Thank you.
You can start from a path graph and then add the edges along this path. You can define the following function:
sage: def caterpillar(L):
....: k = len(L)
....: G = graphs.PathGraph(k)
....: for i,n in enumerate(L):
....: for _ in range(n):
....: G.add_edge(i,k)
....: k += 1
....: return G
Then calling for example caterpillar([3,1,0,7]) will result in a caterpillar graph with a path of length 4 and 3,1,0,7 vertices attached to them in that order.
You can use G = graphs.RandomLobster(20, .5, 0).
Most of the methods are well documented, so please check the documentation of the Random Lobsters generator.
The parameters of graphs.RandomLobster(n, p, q) are the number of nodes n of the generated graph, the probability p of attaching a pending edge to the main path and the probability q of attaching an edge to an edge of previous level. Setting q=0 ensure that you get a Random Caterpillar.
Of course it's random, so two successive calls give different results.
Otherwise, use the method proposed by tmonteil
Asked: 2019-08-05 08:57:15 +0100
Seen: 701 times
Last updated: Aug 05 '19
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